CAB39L elicited an anti-Warburg effect via a LKB1-AMPK-PGC1α axis to inhibit gastric tumorigenesis

Weilin Li, Chi Chun Wong, Xiaoming Zhang, Wei Kang, Geicho Nakatsu, Qinfu Zhao, Huarong Chen, Minnie Yin Yin Go, Philip Wai Yan Chiu, Xiaohong Wang, Jiafu Ji, Xiaona Li, Zongwei CAI, Enders Kwok Wai Ng, Jun Yu*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

46 Citations (Scopus)


Metabolic dysfunction is a hallmark of gastric cancer (GC). In this study, we reported the identification of Calcium Binding Protein 39-Like (CAB39L) as a novel regulator of tumor metabolism in GC. CAB39L mRNA was frequently silenced by promoter methylation in GC cell lines and tissues. Functional studies suggested that CAB39L functions as a tumor suppressor, as overexpression of CAB39L elicited suppression of multiple cancer phenotypes both in GC cells and an orthotopic mouse model; whilst its knockdown promoted tumorigenesis. Mechanistically, CAB39L interacted with LKB1-STRAD complex and induced LKB1, leading to the phosphorylation and activation of AMPKα/β. LKB1-AMPK activation in GC cell lines was tumor suppressive, as metformin (an AMPK activator) inhibited GC cell growth in the CAB39L-silenced cells. Moreover, knockdown of LKB1 reversed growth inhibitory effect of CAB39L, indicating that tumor suppression by CAB39L depended on LKB1-AMPK. RNAseq and gene set enrichment analysis revealed that CAB39L was closely correlated with oxidative phosphorylation and mitochondrial biogenesis. Consistently, CAB39L-induced p-AMPK elicited PGC1α phosphorylation and increased the expression of genes involved in mitochondrial respiration complexes. Accordingly, CAB39L reversed the Warburg effect in GC, as evidenced by enhanced oxygen consumption rate and reduced extracellular acidification rate; inversely, CAB39L knockdown promoted a metabolic shift towards the Warburg phenotype. In GC patients, CAB39L promoter hypermethylation was correlated with poor prognosis. Our data demonstrate that CAB39L is a novel tumor suppressor which suppresses tumorigenesis by promoting LKB1-AMPK-PGC1α axis, thereby preventing a metabolic shift that drives carcinogenesis. CAB39L methylation is a potential prognostic biomarker for GC patients.

Original languageEnglish
Pages (from-to)6383-6398
Number of pages16
Issue number50
Publication statusPublished - 13 Dec 2018

Scopus Subject Areas

  • Molecular Biology
  • Genetics
  • Cancer Research


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